Suspensions for motor vehicles often comprise coil springs of different sizes in order to set the correct spring rate for a particular vehicle. The spring rate of the suspension may be set depending on the weight of the vehicle, the intended use of the vehicle, operator preferences, and/or many other considerations.
In order to be able to meet the wide variety of demands, a large number of coil springs with different spring rates must be kept in stock. During assembly (of the vehicle or the suspension system), when a specific spring rate is required an assembler has to find the correct set of coil springs out of several tens or even hundreds of sets having different spring rates. The system for marking the coil springs may be complicated due to the large number of coil springs. Being able to locate the correct set of springs may be difficult and time consuming. A further disadvantage of using coil springs is that they are heavy and bulky.
In some vehicles a leaf spring is used instead of a coil spring. The leaf spring may be mounted longitudinally or transversely. By using different types of arrangements the characteristic of the leaf spring may be changed.
Leaf spring suspension arrangements have been proposed which include various additional springs and/or other elements by which the characteristics of the leaf spring (the spring rate, for example) may be changed. See, for example, US Patent Application Publication 2010/0320658 A1. Such arrangements are mechanically complicated and do not allow for an easy adjustment of the spring characteristics.